Landoll, U.S. Pat. No. 4,228,277, introduced a pioneering class of hydrophobically modified cellulose ethers which have gained a class recognition as associative cellulosic thickeners. Assignee's pending patent application, Ser. No. 428,912, filed Oct. 30, 1989, details how improved properties are obtained when the alkyl hydrophobes, as taught by Landoll, are replaced with arylalkyl hydrophobes such as nonylphenyl groups. U.S. Pat. No. 4,870,167 discloses that hydrophobically modified nonionic polygalactomannan ethers (guar) can be employed in a variety of uses including oil drilling and recovery. U.S. Pat. No. 4,664,978 discloses a fluorinated product of either methylcellulose or ethylcellulose. A hydrophilic polymeric coating comprising polyvinyl alcohol esterified with perfluorooctanoyl chloride was disclosed in a publication by Stewart, David J.; Purvis, Duncan R.; Lowe, Christopher R. (Inst. Biotechnol., Univ. Cambridge, Cambridge, U.K. CB2 3EF) J. Chromatogr. 1990, 510, 177-187. French Patent Application 2 636 334, "Perfluoroalkylated Polysaccharides, Their Preparation and Uses" discloses grafting 4 to 20 carbon atom perfluoroalkyl groups onto polysaccharide chains of xanthan and carboxymethylcellulose.
While these references indicate that extensive and exhaustive work has been undertaken on polymer modification, it remained for the present invention to reduce to practice the means for providing a new and useful associative thickener 5 utilizing a perfluorinated alkyl hydrophobe.